Cracked plaster ceiling fix

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  #1  
Old 01-27-15, 08:53 PM
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Cracked plaster ceiling fix

I need advice on how to fix plastered ceiling cracks.

The ceiling is made of sheetrock, then a layer of brown coat about 1/4" thick, then textured.

Recently I had a new roof put on. This is a flat roof building so the ceiling is only a bit over 6" (2X8) below the T&G roof deck. The roofing crew as their repaired moisture damaged roof deck, some rafter tails, and fascia, they were doing a bunch of hammering and nailing and after that, I noticed from below some of my plastered ceiling has cracks. Unfortunately, the roof contract contains a damage waiver clause - if they break ceilings, or windows, or shoot a nail into a water pipe etc...none of that they are responsible for, so it's up to me to fix this.

Here are some pictures, it's hard to see so I am posting pictures in pairs. The first one is the original picture, followed by the same picture where I traced the cracks in red lines, to help you see them.













Do I just apply a skim coat of joint compound over the crack? Do I use paper tape or nylon mesh tape?

Thanks in advance for your comments.
 
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  #2  
Old 01-28-15, 03:16 AM
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Is the plaster veneer still sound? tapping on the plaster will reveal a hollow sound if the plaster is no longer bonded to the drywall. Often when repairing plaster you can scratch out the crack and then fill it with a setting compound like Durabond and call it done. It's kind of unusual for plaster to be textured, are you sure it's a plaster veneer and not just drywall and texture?
 
  #3  
Old 01-28-15, 04:07 AM
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This is why I hate textured finishes in general.

One of the pictures seems to show just a finish layer that might be delaminating.If you scrape away at the edges where the cracks are, you may reveal an underlying original finish that may or may not be a smooth surface. If it is then you may want to scrape the areas down to that finish and , as Mark indicated, check to see if the base is delaminated from the lath or the lath and base are detached from the framing. A proper repair is dependent on that assessment first.

If it is all solid but cracked, you can tape the joints but you still have to decide then whether you will try to texture or just smooth out the whole ceiling with joint compound. Textures are very difficult to patch in without being noticeable.
 
  #4  
Old 02-12-15, 05:59 PM
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It is composed of three layers of materials. Same as the wall.

The bottom layer is a gypsum board, about 1/2". Applied over that is another coat of I think they call it a "brown coat", it's like cement but there is no lath underneath, except at corners and wall/ceiling junction. This brown coat is also about 1/2" thick. On top of that is a layer of white egg shell like stuff, and it's very thin, as thin as egg shell. On top of that is like two layers of paint and textures.







Anyway, I made two holes where the crack "intersected". The bottom layer of gypsum board is still OK, looks to be solidly attached to the flat roof framing above. The brown coat has separated somewhat from the gypsum board.

I started to drill around and found one rafter. So I drilled two drywall screws up to bring up the brown coat. The ceiling is back to "level" now, it looks a bit "hollow" in the pics because I dug out the loose bits inside the holes.

I haven't patched anything yet. I am wondering if I should shoot some construction adhesive into the two holes with a caulking gun...not sure.

I am not liking the idea of pulling everything down or cutting a larger opening. The house is from the 1960s, I don't know how much asbestos and lead paint there are in these.
 
  #5  
Old 02-12-15, 06:19 PM
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Since you know where a joist is it should be pretty easy to find the other joists. I would do this. Where ever a crack crosses a joist put a screw or two on either side of the crack Don't rely on the screw to draw up the ceiling push it up first. Maybe use a "T" brace to hold it up. Then use tape like Crack-Tape by strait-Flex or FibaFuse and setting joint compound over the crack. This will leave a smooth repaired area. It will probably take two coats to get it good enough to texture. You have some kind of a stomp texture knocked down. Experiment with a brush or gunny sack or sea sponge or whatever you think might work to dip into some thinned All Purpose joint compound and slap or stomp it against the repair and lap it onto the existing a little. Timing is key. Knock it down by sliding your knife or a trowel over the spots. When it is dry enough it will match pretty closely. If it is too wet it will slick down too smooth and flat. Let it dey, redo it and then when you get a repair you like do it all the same way and prime the patch, paint the patch and let it dry then paint the whole ceiling.
In order to try to match the texture get some drywall scraps and experiment. And remember this: However the texture was done it was done very quickly. You might not be quick but remember that the artist who did it did it quickly. That will help you picture how he did it.
 
  #6  
Old 02-12-15, 08:09 PM
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Rather than just using the drywall screws, you should get some "plaster washers" and use the screws and washers to help hold the plaster up.

Having plaster base coat delaminate from the gypsum lath beneath is not a common occurrence. I would tap the plaster in the general area of the damage and try to determine if there is a more wide scale issue. If you can push on the adjacent surface and notice considerable movement or if you tap and it sounds hollow, I would be concerned about an issue that might warrant investigation by someone who can see it in person. If the base material is a sand aggregate gypsum it can be of considerable weight. A section falling off could do some damage or cause someone a nasty headache.


If everything seems secure enough to carry out repairs as tightcoat suggested then you can skim just the affected area or the entire ceiling and re-texture. To me, it seems like your texture is a spray applied "orange peel" that was knocked down with a trowel afterwards.
 
  #7  
Old 02-12-15, 08:43 PM
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Calvert might be right about a spray job. If the plaster is loose from the lath then carefully use a spade bit to allow yourself to countersink the plasters washers. It makes for a flatter repair.
 
  #8  
Old 02-13-15, 03:55 AM
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Most knockdown texture when I worked in fla was sprayed on, let to set the desired time and then knocked down with a 2' wide knife. With knockdown they spray a splatter coat. That said, you can still apply texture by hand and use a smaller knife for repairs. I've made small repairs with a sponge and used a hopper gun for the larger repairs.
 
  #9  
Old 02-13-15, 05:34 PM
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I am having trouble matching the texture - or even close to it.

I am using regular premade joint compound I bought from Home Depot.

I applied a thin layer, then put my hand inside a plastic bag, then used my finger to mess up the patched area, then waited a few minutes to go over lightly with a knife, and it smoothed off the area.

Should I have waited a certain amount of time before I mess up the wall?

Should I have waited another certain amount of time before I use the knife?
 
  #10  
Old 02-13-15, 06:51 PM
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You might try flinging some thinned out mud against the ceiling with a coarse bristle brush and a short stroke with an abrupt stopping action. Whenever you are ready to do the knockdown you have to have a light touch.
 
  #11  
Old 02-14-15, 04:01 AM
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Also you want the texture to set up some [not dry] before you knock it down with the knife. Knockdown is one of the harder textures to master when it comes to repairs The good thing is it's no big deal to smooth it out and start over while it's wet or sand it down and start over when dry.
 
  #12  
Old 02-14-15, 06:15 AM
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When I patch these cracks, do I enlarge the cracked area into a V-notch, scrape away the existing texture, tape (with mesh tape) and patch with joint compound?

Or simply patch with joint compound?
 
  #13  
Old 02-14-15, 06:42 AM
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If you use 'sticky tape' [mesh] you must use a setting compound to lock it down, otherwise the tape will fail sooner or later.
 
  #14  
Old 02-14-15, 08:41 AM
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Couldn't find a local source of plaster rings. Must have called a dozen of local hardware stores. One said they have it I went there and it's mud ring for electrical boxes LOL.

 
  #15  
Old 02-14-15, 09:32 AM
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Are you looking for plaster rings or plaster washers? Have you tried a drywall supply house?
 
  #16  
Old 02-14-15, 12:57 PM
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Usually have to order washers online. I sometimes buy through "Kilian Hardware" in Chestnut Hill,PA. They have a great web site and will get them to you fast.

If you only need a few, you could use what are known as fender washers. They are heavier gauge metal and are not perforated like plaster washers which do provide a means for allowing the patching compound to lock in to the metal. Any decent hardware store should have the fender washers in 1-1/2" size. You should drill a recess into the plaster like tightcoat mentioned. I usually use a carborundum tipped holesaw but a spade bit would do it for a few holes. You could also tape over the fender washers to compensate for them not having the perforations like a regular plaster washer.

You could also try a supply co. that sells exterior stucco materials. The foam that goes on under EIFS is held on by a fastener and plastic washer that would do the job well enough for a small area.
 
  #17  
Old 02-16-15, 09:41 AM
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I've had good luck matching small areas of knockdown with a dash brush. A das brush is not very costly but is pretty specialized and hard to find so a stiff whisk broom works pretty well.
Thin down some mud to about pancake batter consistency then dip the brush into the mud. hold the brush about a foot away and then use your hand to bend the bristles back and let them go. This will flick some mud off the brush. You can do this a few times before you need to reload the brush. The consistency of the mud and the amount of force behind the flick determine the size of the spots. For a small area I use setting mud for this. It is faster than waiting for the spots do dry and knock down. When it is partly set then knock it down. If it is too soon then wait a little longer. If you waited too long use more pressure. lubricate the trowel of knife with water to keep from dragging the mud.
I have noticed that in a patch the mud usually sets faster on the unpainted area than on the painted area so don't slick down the painted area too much.
On a patch two feet square I would have had it done in the time it took to type this. It might not be knocked down yet but would be sprayed.
 
  #18  
Old 02-17-15, 05:41 PM
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Thanks for all the advice, but this did not come out quite the way I hope.

As suggested, I located the locations of a few joists and drove some screws through the plaster ceiling to bring it back up. Note that the gypsum board above the plaster layer is fine, it's the "over coat" of 3/4" of plaster that seems to have delaminated somewhat.

As I drove the screws into the plaster, more cracks developed around the plaster. I think when the plaster came apart, something got loose inside and wedged in between the gypsum board and the plaster layer, and as I secure it with more screws, I made it worse.

So finally I decided to just pull down the plaster layer. I was able to pry it off pretty clean and now what I have is the original gypsum board on the ceiling.

It is nailed to the framing above but all the nails look rusted.

Here are some pictures.







The gypsum board surface is a bit rough, not paper smooth like modern sheetrock.

I am trying to decide on the next step. I can either tape and mud this board as is, or I can cut a new piece of green board (this is a bathroom ceiling) and hang that right below.

Thoughts?

I need to shower I have plaster dust all over myself.
 
  #19  
Old 02-17-15, 05:46 PM
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Another question I have is either way I go, I need to finish the wall/ceiling joint.

The new ceiling will be smooth, not textured. The walls have knockdown texture.

How would I do the joint? Do I scrap off the knockdown on the top 2" of the walls in order to tape the joints?
 
  #20  
Old 02-17-15, 06:26 PM
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What are the dimensions of the boards you have exposed? What you described just should. To have happened. Something is amiss.
 
  #21  
Old 02-17-15, 06:45 PM
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It's a small bathroom, so the entire ceiling is about 5' by 7'.

I think the reason is they plastered over the original gypsum board. When the roofer worked on the new roof and the rafter tail repairs, fascia, they did a lot of banging and hammering, and the plaster started to separate from the ceiling gypsum board. I am thinking some crumbed piece of plaster got wedged in between so when I tried to screw the plaster layer back up, the crumbled piece of debris caused the new cracks.

Anyways the old plaster is all down now. I can see the old roof leaks that caused all the nails to be rusted.
 
  #22  
Old 02-17-15, 06:48 PM
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Really odd that the base plaster delaminated from the gypsum lath as easily as you say. The roof leaks probably contributed to the delamination. The lath looks like the old standard 16" by 48". At this point I would add the 1/2" layer of moisture resistant drywall or (XP) and you could try just flat taping the edge of that board up against the walls without taping the corner itself. That way you don't really have to get involved with re-texturing anything.

You would have to see how expansion issues affect the wall/ceiling junction. A fine crack may open during seasonal changes which you could just run some acrylic caulk into and clean off any excess with a damp sponge.
 
  #23  
Old 02-17-15, 07:31 PM
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It is almost unheard of for plaster to separate from gypsum lath. If the lath is nice and flat calverts idea of putting up drywall over the lath is probably your best and easiest fix. Use long enough screws.
 
  #24  
Old 02-18-15, 04:55 AM
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I agree, laminating the ceiling with drywall would be your easiest fix. Flat tape the perimeter and then caulk it to the wall to eliminate the need to tape/finish the corners.
 
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